Changes between Version 144 and Version 145 of Documentation/TrunkFunctionality4

Timestamp:

2023-11-18T01:48:11+01:00 (6 months ago)

Author:

egaglo

Comment:

--

Documentation/TrunkFunctionality4

@@ -248 +248 @@
 === Height (of vegetation) ===
 Describes r7451. Vegetation height is dynamic; as the PFT (in particular forests) grow, the height will grow through the allocation. When multiple circumferences classes are used, height has an impact on where the carbon goes. Due to intra-stand competition, more carbon gets allocated to taller circumference classes. Disturbances can change the average stand height. Self-thinning is a natural process in which small trees die because they are out-competed for resources. Environmental mortality is another natural process in which larger trees are killed as they are assumed to be more sensitive to environmental stress. Windthrow is an (optional) process which will disproportionally impact taller trees. In runs using forest management (not currently the default), forests can be thinned from above or below. Forests thinned from above lose tall trees to harvest, while those thinned from below lose small trees. Both actions change the average height of the stand.
-The parameters '''pipe_tune3''' and '''pipe_tune2''' link tree diameter to tree height. Where pipe_tune3 is the tree height (m) for a tree with a diameter of 1 meter. Those parameters determine the diameter-height relationship but the height growth is mostly driven by stand mortality. Many trees need to die early on during stand development to reach realistic height growth rates. That is the reason why the RDI of young stands is rather low (0.3 to 0.4 -> determined by '''d_rdi_xxx_yyy''') Vegetation height has an impact on roughness height (aerodynamic properties of the surface).
+The parameters '''pipe_tune3''' and '''pipe_tune2''' link tree diameter to tree height. Where pipe_tune2 is the tree height (m) for a tree with a diameter of 1 meter. Those parameters determine the diameter-height relationship but the height growth is mostly driven by stand mortality. Many trees need to die early on during stand development to reach realistic height growth rates. That is the reason why the RDI of young stands is rather low (0.3 to 0.4 -> determined by '''d_rdi_xxx_yyy''') Vegetation height has an impact on roughness height (aerodynamic properties of the surface).
 Two variables are output for each PFT: "HEIGHT", which is the average height of the vegetation (averaged across all circumference classes), and "HEIGHT_DOM", which is the dominant height (the height of the largest circumference class). A switch was introduced in r7083 which allows one or the other to be used in the calculation of the roughness height.